My absolute favorite and best way to do it is the Big Con . Although others might say silent and sneaky is better I think not . With the big con if you do the gruppe sechs disguises ,you immediately get access to the vault you don't need to avoid or knock out anybody when entering the vault area .
The Big Con Approach is not only super efficient (given the perilous nature of GTA Online), but it's also quite fun. It allows the player to infiltrate the casino in disguise. This approach, too, helps the player avoid unwanted attention and keep a low profile, which is always helpful in GTA Online.